Irbesartan Does Not Reduce CV Events in AF Patients

March 14, 2011

March 11, 2011 (Hamilton, Ontario) — The Atrial Fibrillation Clopidogrel Trial with Irbesartan for Prevention of Vascular Events (ACTIVE I), a study evaluating the possible role for the angiotensin-receptor blocker irbesartan (Avapro, Sanofi-Aventis/Bristol-Myers Squibb) for the prevention of cardiovascular events in patients with atrial fibrillation, has now been published, showing the drug did not reduce the composite end point of stroke, MI, or death from vascular causes [1].

As reported by heartwire when the study was presented at the European Society of Cardiology 2009 Congress, there was no reduction in the composite primary end point of stroke, MI, death from vascular causes, or hospitalizations for heart failure, but there was a significant 14% reduction in heart-failure hospitalization alone, a secondary end point.

In the study, published in the March 10, 2011 issue of the New England Journal of Medicine, lead investigator Dr Salim Yusuf (McMaster University, Hamilton, ON) and colleagues rerandomized patients included in the ACTIVE clinical-trial program, which included two studies of patients with atrial fibrillation and one or more additional risk factors for stroke. ACTIVE-W, a comparison of warfarin with the combination of clopidogrel and aspirin, and ACTIVE-A, which included patients unsuitable for warfarin, were both reported previously by heartwire .

Among the 9016 patients included in the ACTIVE I study, the rate of stroke, MI, and death from vascular events was equivalent in patients treated with irbesartan and those who received placebo. The addition of heart failure to the composite end point--a combined, prespecified, co-primary end point--did not alter the results. On its own, however, hospitalization for heart failure was 0.5% lower in the irbesartan-treated patients, a benefit that translated into a relative 14% reduction. Overall, there were trends suggesting a reduction in stroke and transient ischemic attack, but these did not reach statistical significance and should also be interpreted cautiously, say investigators.

Yusuf and colleagues point out that that the difference in systolic blood pressure between the treatment arms was just 2.9 mm Hg and that this modest reduction in blood pressure might be one of the reasons for the lack of observed benefit with irbesartan.

Bristol-Myers Squibb and Sanofi-Aventis funded the ACTIVE-AF trial.


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